Novel titanium compound and lubricating composition containing said compound



United States Patent 3,134,737 NOVEL TITANIUM CDMPOUND AND LUBRICAT- ING COMPOSITION CONTAINING SAID COM- POUND Edward L. Kay, Akron, Ohio, assignor to Texaco Inc, New York, N.Y., a corporation of Delaware No Drawing. Filed Aug. 2 1960, Ser. No. 51,537 4 Claims. (Cl. 25242.'7)

This invention relates to a new composition of matter and to an improved lubricating composition containing said composition of matter which exhibits desirably high extreme pressure properties. More particularly, this invention relates to a hydrocarbon mineral and synthetic base lubricating oil containing a titanium derivative of an alkylene bis (chlorophenol) to improve load carrying properties.

There is an ever increasing need for the improvement of the extreme pressure properties of lubricating oils with the development and increase in speeds of new heavy high speed machinery, aircraft engines and propulsion engines. This is particularly true for the lubrication of newly developed jet turbine engines, where it is always desirable to increase the load carrying ability of the lubricating composition to be used in the lubrication of such engines. The present invention relates to an additive possessing extreme pressure action which is particularly useful in the formulation of jet engine lubricating oils.

In accordance with the present invention, an improved lubricating composition having increased extreme pressure properties is obtained by the inclusion of from about 0.25 to about 5.0 weight percent of a titanium derivative of an alkylene bis (chlorophenol) in the base lubricating oil.

A satisfactory method of preparing the organic titanates, which are the preferred additives of the present invention comprises an alcohol interchange reaction between an alkyl titanate and various alkylene bis (chlorophenols) in a titanate-bis phenol mol ratio of from about 1 to 1 and 1 to 2. The reaction product obtained is mixture of the following compounds depending upon the mol ratio used:

3,134,737 Patented May 26, 1964 wherein R is an alkyl group containing 1 to 6 carbon atoms, n is an integer of l to 3 and n is more than 1.

Examples of the tetraalkyl titanates used in the present invention are tetra methyl titanate, tetra ethyl titanate, tetra isopropyl titanate, tetra isobutyl titanate and tetra isoamyl titanate. The lower alkyl titanates are used because of the ease in which the formed alcohols may be removed.

Examples of the alkylene bis (chlorophenols) used in the present invention are 2,2 methylene bis (p-chlorophenol), 2,2 ethylene bis (p-chlorophenol) and 2,2 propylene bis (p-chlorophenol).

The preferred additive of the present invention is a titanate of 2,2 methylene bis (p-chlorophenol) which is the reaction product of a tetraalkyl titanate and 2,2 methylene bis (p-chlorophenol). The preferred range in which the additive is used is from about 0.5 to about 1.5 weight percent.

The specific preparation of the preferred additive is set forth below in Example 1.

The lubricating oils of this invention include hydrocarbon mineral lubricating oils and synthetic lubricating oils. The hydrocarbon oils found to be useful for this invention include oils having a viscosity in the range required for lubricating fluids and in particular hydrocarbon mineral oils which include paraifin base, naphthene base, mixed paraffin-naphthene base and residual oils. The hydrocarbon lubricating base generally has been subjected to solvent refining to improve its oxidation and thermal stability and viscosity-temperature properties as well as solvent dewaxing to remove waxy components and to improve the pour of the oil. Broadly speaking, hydrocarbon lubricating oils having an SUS viscosity at F. of between 50 to 2500 are used in the formulation of the improved lubricants of this invention.

The mineral lubricating oils to which the titanate derivative of this invention is added usually contain other additives designed to impart desirable properties thereto. For example, viscosity index improvers such as the polymethacrylates having a molecular weight ranging from 500 to 25,000 are usually included therein. The V.I. improver normally used is a polymethacrylate having the following recurring structural unit:

wherein R is an aliphatic radical ranging from butyl to stearyl and n is an integer of more than 1.

The use of various metal base organic type additives has been found effective and are generally incorporated in the lubricating oils of this invention, particularly those oils used in high speed, spark ignition and diesel engines to reduce ring sticking, minimize lacquer formation and carbon deposits. The metal alkyl phenolates wherein the alkyl group on the benzene nucleus is of comparatively high molecular weight has been found particularly useful where the mineral lubricating oil is of the type generally employed for the crankcase lubrication of aircraft engines which normally operate at higher power-levels on high octane airplane fuel. The preferred type of hydroxy aromatic compound is an alkyl phenol prepared by alkylating phenol, cresol, xylenol or other alkyl phenol with an olefin polymer to obtain an alkylated phenol wherein the alkyl constituents on the benzene nucleus contain a total of at least 15 carbon atoms and preferably at least 18 to 30 carbon atoms. A combination of magnesium and zinc salts of alkyl phenols wherein the alkyl groups have from 18 to 30 carbon atoms has been found particularly useful. The magnesium alkyl phenolate is employed within the range of 0.5 to 2.0 wt. percent and he zinc alkyl phenolate is employed in conjunction with the magnesium phenolate in a proportion of 0.25 to 1.5% by wt. on the basis of the total lubricating oil composition. Lubricating oil compositions containing the desired combination of magnesium and zinc alkyl phenolates are set forth in US. Patent No. 2,674,577 to Frederick C. Mc- Coy, Bill L. Benge, Edwin C. Knowles and Charles C. Town, issued April 6, 1954.

The hydrocarbon lubricating oils of this invention may also contain other useful additives such as metal sulfonates to afford additional detergent-dispersant properties, metal dialltyl dithiophosphates to afford additional corrosion and oxidation resistance, anti-foam agents such as silicone polymers in the amounts of about to 200 parts per million, etc.

The esters which constitute the synthetic lubricant composition of this invention are broadly described as esters of hydrocarbyl carboxylic acids. They are high molecular weight materials of lubricating oil characteristics derived from alcohols which are usually aliphatic alcohols containing 1 or more hydroxyl radicals and monocarboxylic acids which are usually aliphatic carboxylic acids containing 1 or more earboxylic acid radicals.

Widely used synthetic ester lubricants are aliphatic diesters of aliphatic dicarboxylic acids containing 612 carbon atoms. From the standpoint of cost and availability, the preferred dibasic acids are adipic acid, sebacic acid and azelaic acid. The aliphatic alcohols used to form the diesters usually contain at least 4 carbon atoms and up to or more carbon atoms. C to C alcohols are most commonly used. Ether alcohols such as Cellosolve and Carbitol may also be used in the formation of the aliphatic diesters of organic dicarboxylic acids used as the lubricating base in the compositions of this invention. Alcohols containing 2 or more hydroxyl radicals and no hydrogen substituted on the beta carbon atom such as trimethylol propane and pentaerythritol have proven particularly effective in formulating stable high temperature ester lubricants.

Examples of alkyl esters of aliphatic carboxylic acids are the following: di-isooctyl azelate, di-Z-ethylhexyl sebacate, di-Z-ethylhexyl azelate, di-Z-ethylhexyl adipate, dilauryl azelate, di-sec-amyl sebacate, di-Z-ethylhexyl alkenyl-succinate, di-Z-ethoxyethyl sebaeate, di-2-(2'- methoxyethoxy) ethyl sebacate, di-2-(2'-ethylbutoxy) ethyl sebacate, di-Z-butoxyethyl azelate, di-2-(2'-butoxyethoxy) ethyl alkenyl-succinate, pentaerythritol tetracaproate and trimethylol propane tri-isooctanoate.

In addition to such esters, polyester lubricants formed by a reaction of an aliphatic dicarboxylic acid, a dihydroxy compound and a monofunctional compound, which is either an aliphatic monohydroxy alcohol or an aliphatic monocarboxylic acid, in specified mol ratios are also employed as the synthetic lubricating base in the compositions of this invention; polyesters of this type are described in US. 2,628,974 on Polyester Synthetic Lubricants, which issued to R. T. Sanderson on February 17, 1953. Polyesters formed by reaction of a mixture containing specified amounts of Z-ethyl-1,3-hexanediol, sebacic acid, and Z-ethylhexanol and by reaction of a mixture containing adipic acid, diethylene glycol and 2-ethylhexanoic acid illustrate this class of synthetic polyester lubricating bases.

The sulfur analogs of the above-described esters are also used in the formulation of the lubricating compositions of this invention. Dithioesters are exemplified by di-2-ethylhexyl thiosebacate, di-n-octyl thioadipate and the dilaurate of 1,5-pentanedithiol; sulfur analogs of polyesters are exemplified by the reaction product of adipic acid, thioglycol and 2-ethyll1exyl mercaptan.

Alkyl-substituted phenols are usually incorporated in the lubricants of the invention as anti-oxidants. The preferred and most commonly used alkyl phenol antioxidants is 2,6-di-tertiary octylphenol; 2,6-di-tertiary amyl-4-nethylphenol; and 2,6-di-isopropyl-4-methylphenol. Hindered phenols of this type are employed in concentrations between 0.1 and 1.0 weight percent.

Although hindered phenol type anti-oxidants are the most widely used anti-oxidants in the lubricant compositions of the invention, aryl-substituted amine anti-oxidants such as phenylnaphthylamine, phenylene diamine, and diphenylamine are also used in lubricants in conjunction with the extreme pressure additive of the invention. The amine anti-oxidants are employed in the same concentrations as the hindered phenol anti-oxidant. Organic silicones are normally incorporated in the lubricants of the invention to impart thereto anti-foam properties. The silicones are usually of the dialkyl or mixed alkyl-aryl silicone type. Dimethyl silicone is normally employed as the anti-foam agent. The silicone is incorporated in the lubricant by means of a kerosene concentrate containing 5 to 15 weight percent silicone. A very satisfactory antifoam agent is a kerosene concentrate 10 weight percent dimethyl silicone. The kerosene concentrate is employed in an amount sufficient to provide a silicone polymer concentration of from 50 to 250 parts per million based on the total lubricant composition.

To demonstrate the excellent improvement in the loadcarrying ability of lubricating oils containing the titanate derivatives, of this invention, a high speed gear scuff test was used. Other alkyl titanates were also tested in the Ryder Gear Test in order to show the general lack of extreme pressure properties of the other titanates and the surprising results obtained with the class of titanates of the present invention. This test is intended for the evaluation of the scuff-limited load-carrying ability of those lubricants used in reduction and accessory drives of turbo-jet and turbo-prop engines. The method of test provides for the running of two spur gears in a Pratt and Whitney Gear and Lubricant Tester (also termed the Ryder Gear Tester). The oil inlet temperature to the gears was i5 F. The face width of the driven gear was 0.937 inch and the face width of the driving gear was 0.25 inch. The dynamometer speed of the Gear Tester was 3830 rpm. (equivalent to a gear speed of 10,000 r.p.m.) and loading pressure of 2 /2 p.s.i. applied during break-in. After running for 10 minutes, the tester was shut down and the driving gear removed and an estimate of the percentage of tooth area scuffed on each tooth of that gear was made. The gear was replaced and the above procedure continuously repeated using a higher loading pressure with increments of 5 p.s.i. at each repetition until 22.5 percent of the total tooth face area on the driving gear had been scuffed, the load corresponding to this point being considered the scuff load. Scuffing is defined as that degree of wear or abrasion which obliterates the axial grinding marks on the gear tooth. The loading pressures used were as follows: 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 8O p.s.i. and up. A tooth load conversion factor of 18.5 sq. in. which was a constant calculated from measured data from the Tester, was multiplied by the loading pressure at the scuff load and divided by the width of the driving gear (0.25) to obtain the tooth load in pounds per inch.

EXAMPLE I.PREPARATION OF A 2,2'-METHYL- ENE BIS (p-CHLOROPHENOL) TITANATE DE- RIVATIVE 1.0 mol of 2,2'-methylene bis (p-chlorophenol) was reacted with 0.5 mol of tetraisopropyl titanate in a toluene solution at reflux temperature. Isopropyl alcohol was then removed from the reaction medium as an azeotrope with toluene. The reaction product obtained was a mixture of titanates as previously described wherein R is isopropyl (C H' and n is 1.

The results obtained using the above test procedure on various lubricating oil compositions including that of the invention are set forth in the following table:

Table I HIGH SPEED RYDER GEAR TESIT titanate The above table indicates the very great and surprising improvement in the load-carrying ability of the base oil containing the 2,2-rnethylene bis (p-chlorophenol) titanate additive of the present invention. The MIL-L25 336 Specification requires approximately 3000 pounds per inch (p.p.i.) minimum Ryder value for a high load-carrying turbo aircraft oil. The above Table I also demonstrates the inability of other titanates to impart the excellent improvement in the load-carrying ability to the base oil.

Base Oil A in the above table was di 2-ethylhexyl sebacate.

The load-carrying ability of the composition of the present invention was also demonstrated in the Mean Hertz Load Test. The procedure and apparatus for this test is fully described in US. Patent No. 2,600,058. The results of the Mean Hertz Load Test on Lubricating Oil compositions of the present invention are set forth in the following table:

Table II MEAN HERTZ LOAD TEST Oil: Load, kg. Base Oil A 15 Base Oil A plus 0.67% (wt.) reaction product of Example 1 23 From the above tests as illustrated in Tables I and II, it is seen that the load carrying ability of lubricating oils can be considerably increased by the addition of the organic titanium derivative of the present invention and that this load carrying improvement property of the compounds of this invention are not present in organic titanate compounds in general.

I claim:

1. An organic titanium compound mixture consisting of:

6 and (III) C| R 5R Ow ing C1 C1 11' wherein R is an alkyl group having 1 to 6 carbon atoms, n is an integer from 1 to 3 and n is more than 1.

2. An organic titanium compound mixture consisting of:

(II) O C1 (ROM-Ti CH2 I O on 5 CHr-O and (III) Ti Han (II) Cl )i H0u and (III) on Ti--O O- $3 Q-wmnwherein R is an alkyl group having 1 to 6 carbon atoms, n is an integer from 1 to 3 and n' is more than 1.

'2 8 4. A lubricant composition comprising a major portion and of a lubricating oil and 0.25-05 weight vpercent of an 111) OR organic titanium compound mixture consisting of:

5 OIR -CH3 Tl bH, 01 b1 u 10 wherein R is an alkyl group having 1 to 6 carbon atoms 0 Cl and n is more than 1.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AN ORGANIC TITANIUM COMPOUND MIXTURE CONSISTING OF: 